A conventional brushless DC motor is controlled by a driver IC which switches a current direction based on the position of a magnetic pole detected by a magnetic pole position sensor, such as a Hall element. It is difficult to make the conventional motor thin since the motor, which has an armature including a motor core (stator core) and a coil wound around the stator core, is necessary to dispose the coil and the magnetic pole position sensor.
However, smaller, thinner brushless DC motors are demanded.
A conventional thin brushless DC motor disclosed in the Japanese Laid-open Patent No.5-68362 will be described. FIG. 19 shows the configuration of the thin brushless DC motor.
As shown in FIG. 19, a conventional brushless DC motor includes magnet rotor 56 around armature 58. Driver IC 63 which drives the motor through switching a current flowing in coil 60 of armature 58 is provided on substrate 62, and is disposed at the center of armature 58. Substrate 62 on which driver IC 63 is mounted is placed on shielding board 64 and is fixed to armature 58. Rotatable magnet rotor 56 is held by rotor frame 57, and is disposed at a position opposing armature 58.
Magnetic pole position sensor 65 for detecting the position of a magnetic pole of magnet rotor 56 is disposed on substrate 62. Driver IC 63 receives a signal output by magnetic pole position sensor 65, and controls the current flowing in coil 60 of armature 58. This allows armature 58 to operate as an electromagnet, and to generate a rotation torque on the magnet rotor by attraction and repulsion between magnet rotor 56 and the magnetic pole.
In the above conventional brushless DC motor, substrate 62 on which magnetic pole position sensor 65 and driver IC 63 are provided is disposed with a gap from a coil end of the stator core of armature 58. Therefore, the position of the coil end and the thickness of substrate 62 restrict the thickness of the motor. This restriction limits thinning of the conventional brushless DC motor.